In Czech, it's 'Svaty Vaclave' (pronounced votz-lahv; a lone 'c' has the sound of 'tz').  'Svaty' is 'saint'.  Wenceslaus (Vaclav) was also not a king, but a Duke of Bohemia which is today a part of the Czech Republic but was then a region torn between paganism and Christianity.  Vaclav was 15 when his father, a Christian, died.  His mother, a pagan, became Regent and immediately banned Christianity.  A few years later, an older Vaclav retook power from his mother, the Regent, and established Christianity as the official state religion.  One day as Vaclav walked to church, his brother Boleslaus (a pagan) and his henchmen murdered him, making him a martyr. 

This statue of St. Vaclav is at the end of Wenceslaus Square (Václavské námesti).

Wenceslaus Square (Václavské námesti) is not really a 'square'; it's about 1km of pedestrian mall.  You're seeing about half of it in this picture and you can see Svaty Vaclave on his horse way up there at the end.  For you big-time-shoppers, there is big-time-shopping on this street; all the biggest names in fashion have storefronts here.